As shown in FIG. 1(a), the data format of a compact disc of the compact disc digital audio system is such that one data frame consists of 588 channel-bits including a one-symbol (eight bits) subcode area. The subcode, completed using 98 data frames, is constituted of eight 98-bit channels P, Q, . . . , W, as shown in FIG. 1(b). The subcode in the channel Q (Q subcode) consists of 98 bits or 2-bit synchronizing signal S.sub.0, S.sub.1, a 4-bit control signal, a 4-bit address signal, a 72-bit data signal, and 16-bit parity check signal, as shown in FIG. 1(c). The data signal has three modes 1, 2 and 3. The mode is determined by the preceding 4-bit address signal as shown in Table 1.
TABLE 1 ______________________________________ mode address signal ______________________________________ mode 1 0001 mode 2 0010 mode 3 0011 ______________________________________
The Q subcode in the mode 1 is time data in which are recorded the time which has elapsed from the beginning of playing of a certain music piece in the disc (referred to as "piece time" below) and the time which has elapsed from the beginning of playing of the first piece in the disc (referred to as "accumulated time" below). This time data is represented in the BCD code in respect of minutes, seconds and frames, two digits and eight bits each. There is provided an 8-bit blank between said piece time data and the accumulated time data. This piece time data is preceded by 8-bit data showing the number of pieces in the disc and 8-bit index data. The Q subcode in the mode 2 and mode 3 provides data on the catalogue number, maker number, country number, and the like.